Gear lapping apparatus



p 1940. J. M. CHRISTMAN GEAR- LAPPING APPARATUS Filed Nov. 30, 1936 5 Sheets-Sheet l p 1940- J. M. CHRISTMAN 2,215,750

GEAR LAPPING APPARATUS Filed Nov. so 1936 5 Sheets-$heet ,2

Tl .z 4 "E" 1/ 7 P 1940. J. M. CHRISTMAN GEAR LAPPING APPARATUS Filed Nov. 50, 1936 5 Sheets-Sheet 5 p 4 J. M. CHRISTMAN 2,215,750

GEAR LAPPING APPARATUS Filed Nov. so, 1936 5 Sheets-Sheet 4 Shimmy Sept. 24, 1940.

,J. M. CHRISTMAN GEAR LAPPING APPARATUS 5 Sheets-Sheet 5 Filed Nov 30, 1936 Patented Sept. 24, 1940 UNITED STATES OFFICE GEAR LAPPING APPARATUS Application November 30, 1936, Serial No. 113,491

15 Claims.

This invention relates to apparatus for improving radially toothed machine elements such as gears and the like and is more particularly concerned with the lapping or grinding of gear teeth after the formation of the teeth by the usual milling, hobbing, shaving or other cutting operations, and either before or after hardening.

It is common practice in the art to which this invention relates to improvethe meshing of toothed gears by a lapping operation which involves the engaging of the gears with a lap member having corresponding teeth and effecting relative reciprocation between the gear and the lap members, a suitable abrasive being supplied to the cooperating toothed surfaces. For example, an externally toothed gear and an internally toothed lap, the latter being preferably hardened and having teeth affording therebetween recesses within which the gear teeth may be received snugly or with a slight clearance, are aligned axially and are reciprocated in an axial direction, means beingprovided to simultaneously urge one of the cooperating members to rotate with respect to the other to apply circumferential pressure between the cooperating teeth.

A machine adapted to perform the described operation is disclosed in my application Serial No. 17,728, filed April 22, 1935, and the present invention contemplates an improvement thereof. The machine in question comprises, generally, means for supporting a lap, means for support ing a gear for vertical reciprocation in engagement with the lap, and driving means for producing the said reciprocal motion. According to said disclosure, the gear to be lapped is secured at the end of a vertical shaft by means of a nut or other conventional device for securing the gear rigidly to the shaft. Inasmuch as it is desirable to release the gear from such rigid engagement at frequent intervals for the purpose of indexing the gear with respect to the lap, or of exchanging a new gear for a finished one, the present invention is directed to novel and improved means for elevating the gear out of engagement with the lap, and for facilitating engagement and disengagement of the gear and. shaft in order to permit the speedy accomplishment of the aforesaid operations,

A further object of the present invention is the provision of suitable means for engaging, and securing to the shaft, gears of special forms, for example, of the various types customarily employed in the transmissions of motor vehicles. Other and further objects, features and advantages will appear from the description Which (Cl. l.---157) follows, together with the accompanying drawings in which:

Figure 1 is a side elevation of a gear lapping machine to which the present invention is applicable;

Figure 2 is a vertical section of the gear engaging mechanism of Figure 1;

Figure 3 is a vertical section of a modified form of gear engaging mechanism;

Figure 4 is a front elevation of the mechanism of Figure 3;

Figure 5 is a bottom view of the mechanism of Figure 4;

Figure 6 is a horizontal section on line li6 of Figure 4;

Figure? is a vertical longitudinal section of a second form of gear engaging mechanism embodying the present invention;

Figure 8 is a vertical transverse section of a portion of the mechanism of Figure 7;

Figure 9 is a fragmentary section on line 9-9 of Figure 8; I

Figure 10 is an exploded view of a portion of the mechanism of Figures 7 and 8;

Figure 11 is a vertical section of a third form of gear engaging mechanism embodying the present invention;

Figure 12 is an enlarged detail of the gear engaging means of Figure 11;"

Figure 13 is a horizontal section on line |3-|3 of Figure 12; l

Figure 14 is a horizontal section on line I l-l4 of Figure 11;

Figure 15 is a vertical section of a still further form. of gear engaging mechanism embodying the present invention;

Figure 16 is a horizontal section on line 16-46 of Figure 15;

Figure 17 is a horizontal section on line ll'-l1 of Figure 16; and

Figure 18 is an enlarged detail of the gear engaging means of Figure 15.

. In order to facilitate an understanding of the invention, reference is made to the embodiment thereof "shown in the accompanying drawings and detailed descriptive language is employed. It will. nevertheless be understood that no limitation of the invention is thereby intended and that various changes and alterations are contemplated such as would ordinarily occur to one skilled in the art to which the invention relates.

As set forth above, the gear lapping machine to which the present invention is applicable is adapted to impart relative reciprocal movement between a gear and a lap, and the particular embodiment disclosed herein provides for such reciprocal movement in a vertical direction. More specifically, the machine illustrated in Figure 1 is of the type in which the lap is provided with an internal toothed portion and is retained against movement, the gear having external teeth and being reciprocated in meshing relation with the lap. Thus the machine may comprise a frame including a base It] and a head portion overlying the base, the head portion being supported by a standard l2 rising from the base. Gear engaging mechanism I3, which will be hereinafter more fully described, is provided with an upwardly directed boss M which may be keyed or otherwise secured against rotation on a shaft l5. The gear engaging mechanism is rigidly secured, at its upper end, to the shaft I5 by suitable clamping mechanism indicated at l6. Shaft I5 is supported adjacent the upper end thereof in a bearing guide ll and is operatively connected by means of a pitman it .to an eccentric l9 formed on or secured to a shaft 25, the latter being carried by the head portion of the frame and having secured thereto at its outer end a pulley 2| which may be driven by a belt 22 from a motor 23.

It will be appreciated that by means of the mechanism thus far described, rotation of the shaft 20 will effect reciprocation of the shaft i5 and the gear engaging mechanism lit. The latter engages and supports the gear to be lapped in meshing relation with a stationary lap 25 which may be supported rigidly on the base l9 of the frame in any suitable manner.

Mechanism for imparting rotary motion to the shaft l5 and gear engaging mechanism I3 is indicated generally at 25, but since this mechanism forms no part of the present invention, it will not be further described.

The gear engaging mechanism illustrated in Figure 2 is particularly adapted for use in lapping gear clusters such as are commonly employed in automotive transmissions and is illustrated in connection with a gear cluster 25 comprising a shaft 21 provided with gears 28, 29, 3!], and 3|, formed integrally therewith. It will be appreciated that each of the gears comprising the cluster will be lapped in a separate operation, and it is obvious that the vertical relationship between the reciprocating shaft I5 and the lap 24 will be different for each gear. This variable relationship may be accomplished by the provision of suitable means for adjusting the position of the lap and/or the length of the shaft I5, but most expediently the several operations referred to are performed in several machines, each machine being adapted to lap one particular gear of the cluster. The machine illustrated in Figure 1 is arranged and adapted for lapping the lower-most gear 3| of the cluster.

The gear engaging mechanism illustrated in Figure 2 comprises a casing 40 in which is slidably mounted a sleeve 4| which is pivotally supported as at 42 by a link 43. The latter is pivoted at A l to a crank arm 45 carried by a shaft 45, upon the outer end of which is secured a lever ll (Figure 1). A shaft 48 is secured within the sleeve M by means of a pin 49 which extends through a slot 50 formed in the shaft 48, thereby permitting limited relative movement between supported by the head 5|, and between the lower end of the sleeve ll and the collar 52 there are provided a number of disc springs 53, whose function will be described hereinafter. A carrier 54 is threaded upon the lower end of the casing 49 and is provided with a removable gear supporting member 55, the bearing surface between the carrier and gear supporting member being spherical and both the carrier and the gear supporting member being slotted as at 56 to permit the lateral insertion and removal of the shaft 21 of the gear cluster 26. By reason of the spherical bearing surface between the gear supporting member 55 and the carrier 54, the former is enabled to compensate for any lack of parallelism between the respective faces of the gear 28, which is gripped between the gear supporting member 55 and the collar 52.

It will be apparent from the foregoing description that when the lever 41 is in its lower position as illustrated in Figure 1, and the various parts of the gear engaging mechanism therefore occupy the positions illustrated in Figure 2,

the sleeve 4| will be elevated, carrying with it the shaft 48 and collar 52, thus releasing the gear 28. The operator may then manually lift the gear cluster, by taking hold of the gear 28 and rotating it to the desired extent. Upon completion of the lapping operation, the gear 28 may be released in the described manner, and the gear cluster raised until the gear 3| is disengaged from the lap, whereupon the gear cluster may be removed laterally through the slot 56 and a new gear cluster inserted.

It will be apparent from the foregoing that the described mechanism provides means whereby the insertion, indexing, and removal of successive gear clusters may be easily accomplished in a fraction of the time which would be required in securing or releasing a gear secured by bolts or other conventional means.

The gear engaging mechanism illustrated in Figures 3-6 is adapted for use in connection with machines intended for lapping gears 29 and 30 of the cluster 25, and differs functionally from the mechanism of Figure 2 in that it provides for moving the gear Cluster through a greater distance in order to engage and disengage the lap and the gear to be lapped. It will be obvious, for example, that in placing the gear 29 in engagement with a lap, the portion of the cluster beyond gear 29 and including gears 30 and 3| must be projected through the lap, thus requiring a more extensive movement of the gear cluster than is the case when gear 3| is to be lapped. Thuis, also, when the cluster is to be removed from the machine, it will be necessary to elevate it until the gear 3| reaches a point above the lap 24 before the gear cluster may be removed laterally through the slot in the carrier. In order to provide for the aforesaid extended movement, the mechanism illustrated in Figures 3-6 comprises a casing 6!] in which is slidably mounted a carrier 9|, keyed to the casing 60 by means of pins 62. Within the carrier BI is slidably mounted a sleeve 63, which is connected to a shaft 64 by means of a link 95 and crank arm 66, just as in the case of the mechanism previously described. The carrier BI is provided with a removable gear supporting member 61, also as in the case of the previously described form of the invention. A shaft 68 is mounted within the sleeve 63 and secured thereto by means of a pin and slot engagement as indicated at 69. A collar III supported by the head II of the shaft 68 is urged downwardly by the disc springs 12 surrounding the shaft 68.

It is believed that the operation of the described mechanism will be readily understood. With the parts in the position illustrated the gear 28 is securely gripped between the collar Ill and the gear supporting member 61, the springs 12 serving to compensate for variations in thickness of successive gears. If it is desired to elevate the gear cluster for indexing, or to remove it and substitute another piece of work, the lever I3 is elevated, rotating the shaft 64 and with it the crank arm 66, thus raising the sleeve 63 and releasing the grip of the collar I upon the gear 28. However, since the lower portion of the gear cluster is projecting below the lap, it is apparent that the entire gear cluster must be elevated to a considerable extent before its removal will be possible. This may be accomplished by further elevating the lever I3 when the collar I will be brought against the surface 14 of the carrier fiI, elevating the latter until the surface I5 engages the lower end of the casing 60. The gear 3| will then be above the lap and the gear cluster may be removed later-ally as previously described. It will be obvious that the gear may be indexed by raising it to an intermediate position and manually rotating it by taking hold of gear 29.

Rotation of the collar is prevented by the ears I6 (Figure 6), and rotation of the gear supporting member I5! is prevented by means of a pin 'I'I engaging a slot 18 in the gear supporting member (Figure 4). Thus, rotation of the gear cluster, when in operative position, is effectively prevented.

The gear engaging mechanism of Figures 7-10 is adapted for use in connection with gears such as that illustrated in Figure 7, which is of the type commonly employed as a reverse gear in automotive transmissions. In this embodiment ofthe invention there is employed a casing 89 comprising an upper section 8| and lower section 92 connected by bolts 83. A carrier 84 is slidably mounted within the casing 80 and is connected with a shaft 85 by means of a link 96 and crank arm 81. The upper end of the carrier 84 is formed in two sections 88 and 89 adapted to be bolted together and providing space therebetween for receiving the disc springs 9!], which are employed for the same purpose as that described in connection with the previous embodiments of this invention, sufficient vertical clearance being provided between the sections 88 and 89 to permit slight relative movement thereof, whereby downward thrust applied by the link 86 may be transmitted through the springs. A bearing extension IN is threaded into the lower end of the carrier 84 and is adapted to engage the upper side of the gear 92. A shaft 93 extends through the bearing member M and carrier 84 and is provided with a cross-head 94, secured by means of a pin 95. Opposed flanges 96 formed upon the cross-head 94 are provided with serrations 91 adapted to engage corresponding serrations 98 formed upon a ring 99 carried by the casing 80, thus preventing rotation of the shaft 93.

With the parts in lowered position as illustrated in Figure '7, the gear 92 is firmly gripped between the bearing member 9| and a gear supporting member IIlIl, secured at the end of shaft 93 by means of a bolt I III, and is at its lower-most position, in engagement with its lap. When the lever I02 is elevated, the carrier 84 rises, carrying with it the bearing member 9I, thus releasing the gear 92. Further movement of the lever I92 will cause the shoulder I03 of the carrier 84 to engage the underside of the cross-head 94 of the shaft 93, elevating the latter and with it the gear 92, thus taking the latter out of mesh with its lap. The gear 92 may then be manually indexed and again lowered into engagement with the lap, or it may be removed and a new gear substituted, by unscrewing the bolt IIII and removing the gear supporting member III.

In order to support the movable mechanism in elevated position during a change of gears, spring pressed dogs I04 are provided in the casing (Figures 8, 9) and are adapted to engage in depressions I05 formed in the crank arm 81.

The form of gear engaging mechanism illustrated in Figures 11-14 is especially adapted for use with a gear I09 of the type best shown in Figure 12, having a second set of teeth, for example, clutch teeth, spaced from the gear teeth to be lapped. In this form of the invention the carrier III] is slidably mounted within a casing III, .and. within the carrier III] is slidably mounted a cylindrical member I I5, which is keyed to the carrier I III as at I I6. A shaft I II is pinned to the member II5 as at H8, permitting relative rotary motion therebetween, as well as limited relative vertical displacement. The head II9 of the shaft II! is connected to the shaft II2 by means of a link H3 and a crank arm H4, and a plurality of disc springs I20 are interposed between the head II9 and the cylindrical member I I5, for the purpose stated in connection with the previously described forms.

A toothed ring I2I, secured at the bottom of the casing III, engages corresponding teeth I22 formed on the carrier I II], preventing relative rotation between the casing and carrier. Seated near the lower end of the member H5, and retained by any suitable means, such as'a collar I23, disc I24 and bolt I25, is an annular member I26 having a downwardly projecting flange I21 which is toothed at its lower edge. Coil springs I28 are interposed between the carrier III) and annular member I26. A spring ring I29 is seated in a groove formed adjacent the lower end of the carrier III], and one end of the ring I29 projects through an aperture I39 in the wall of the carrier. Internally of the extreme lower end of the carrier are formed teeth I3I, corresponding in number to the clutch teeth I32 of the gear N19.

The gear Hi9 may be inserted in the engaging mechanism by first rotating shaft I I2 by means of a lever (not shown) so as to raise the carrier I I9 into engagement with a shoulder I33 formed on the casing I I I, when further upward movement of crank II I will result in compression of springs I29 and seating of the annular member I29 against the carrier III]. With the parts in this position, the clutch teeth I32 of the gear I99 may be passed upwardly between the teeth I3I, after which the gear is rotated a distance of one half tooth. When this has been done the inwardly projecting end of the ring I29 will be engaged between two of the clutch teeth (Figure 13) and the latter will rest on top of the teeth I SI of the carrier. If now the shaft H2 is rotated so as to lower the mechanism out of engagement with the shoulder I33, springs I28 will cause the annular member I26 to be depressed until the downwardly projecting teeth thereon are seated between the clutch teeth I32 of the gear I59, the latter being securely retained against vertical or rotary motion relative to the engaging mechanism. Further rotation of the shaft I I2 will then lower the mechanism until the gear I59 engages its lap.

By reversing the foregoing steps the gear I59 may be removed. In order to index the gear it is only necessary to elevate the mechanism until the gear I59 is clear of the lap. The teeth I22 of the carrier will then be disengaged from the toothed ring I2I, and the gear carrier IIEI and gear I59 may be rotated manually to effect the desired indexing operation.

The mechanism of Figures 15-18 is adapted for engaging a gear I of the type having internal helical teeth. Here a carrier I5I is slidably mounted within a casing I52, and is connected with a shaft I53 by the link I55 and crank arm I55. The enlarged upper portion of the carrier I5I is in two sections, a head I55 and a sleeve I51, threaded together, the latter being flanged as at I48. The lower cylindrical member I59 of the carrier I5I is provided with an annular shoulder I 41, overlying the flange I58 and forming therewith a vertical driving connection between the upper and lower portions of carrier I 55, while permitting relative rotary motion therebetween. The disc springs I53 are disposed between the head I56 and the cylindrical member I 19 for a purpose generally similar to that previously explained in connection with the other embodiments. A shaft I59 extends centrally of the carrier I5I, and is provided with a cross-head I65, extending through slot I 36 in the cylindrical member I59, the toothed ends of which cross-head engage with a correspondingly toothed ring IIiI, secured to the casing I522, in order to prevent rotation of the shaft I59 and member I45, relative to the casing I 52.

A helically toothed member I52 is threaded into the lower end of member I59, and is splined to shaft I59 as at I53. A second helical toothed member I55 is keyed onto the end of shaft I59, being retained in place by a nut I55. A coil spring I55 surrounds the shaft I59, and is under compression between the member I52 and a collar I67, which is in turn retained by a pin I58. The shaft I59 and member I 5 5 are thus normally urged upwardly relative to the carrier I5I and member I62.

A pin I69, slidably carried in the head of the carrier I5I, rests upon the cross-head I 60 of shaft I59, and in turn supports a flanged disc I'IIJ. If the mechanism is elevated, by rotating shaft I53, until the flanged disc I "III encounters the shoulder III of the casing I52, any further rotation of the shaft I53 will cause the carrier I5I to be slightly raised with respect to shaft I59, compressing spring I56, and moving toothed member I54 away from member I52. When in this position the helical teeth of the respective members align to form, in effect, a single set of helical teeth, matching the internal helical teeth of the gear I55. The latter may be slipped into place on the members I52 and I64, after which the mechanism is released to permit the spring I66 to come into play, urging the shaft I59 and member I64 upwardly with respect to carrier I5I and member I62. This slight movement results in a wedging action between the teeth of the members I62 and I64 and the internal teeth of gear I50, securing the latter rigidly in place. The mechanism may then be lowered to the full extent, bringing gear I50 into operative relationship to its lap. During the final part of the downward movement of the link I54, the cross-head I50 seats on the ring I6I, preventing further downward movement of the shaft I59, and a thrust is transmitted through the springs I58 to the cylindrical member I49, whereby the downward thrust imposed on the latter by the springs I66 is increased, thus increasing the wedging action on the internal teeth of gear I50.

Obviously, gear I55 may be removed by reversing the aforesaid steps. The gear may be indexed merely by elevating the mechanism sulficiently to raise the gear out of its lap, when the cross-head I will be out of engagement with the toothed ring IBI, permitting the gear I50, shaft I59, and cylindrical member I59, to be manually rotated to index the gear.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. In gear lapping apparatus, gear engaging mechanism comprising a relatively fixed member, a carrier associated with said member for telescoping movement with respect thereto, gear clamping means associated with said carrier, means for causing relative movement between said carrier and said member, to withdraw the clamped gear from operative position in engagement with the lap, and automatic means for actuating said clamping means to release the gear upon initiation of such relative movement.

2. In gear lapping apparatus, gear engaging mechanism comprising a relatively fixed member, a carrier movably associated therewith, gear clamping means associated with said carrier, means for moving said carrier into and out of gear lapping position, and means positively locking said gear against rotation relative to said member when in gear lapping position only.

3. In gear lapping apparatus, gear engaging mechanism comprising a relatively fixed member, a carrier movably associated therewith, gear clamping means associated with said carrier, and means for clamping said gear and moving said carrier and gear into gear lapping position, said clamping means being actuated as a result of and during the final portion of such movement of said carrier.

4. In apparatus of the character described, a carrier member and a removable gear supporting member seated therein, the engaging surfaces of said members being spherical in form, both of said members being slotted to receive a gear shaft.

5. In apparatus of the character described, a carrier member and a removable gear supporting member seated therein, the engaging surfaces of said members being spherical in form, means positively locking said members against relative rotary movement therebetween about the axis of the gear to be supported, a lap support, a lap supported thereon, and means for effecting relative reciprocation of said carrier member and said lap in the direction of said axis.

6. In gear lapping apparatus, gear engaging mechanism comprising a relatively fixed member,

a carrier associated with said member for tele-;

a casing adapted to be secured to said shaft, a

carrier slidable within said casing, a member slidable within said carrier, means associated with said member forclamping a gear against said carrier, means for moving said member to release said clamping means, and means whereby the continued movement of saidmember serves to move said carrier and gear from gear lapping position. 1

8. In gear lapping apparatus, gear engaging mechanism comprising a supporting-casing memher, a carrier slidable within said casing, a cylindrical member slidable within saidcarrier, means for clamping a gear between said carrier and said cylindrical member, and means for moving said carrier and gear into gear lapping position, a lap support, a lap supported thereon, and means fpr effecting relative reciprocation of said supporting casing member and said lap,

9. In gear lapping apparatus, gear engaging mechanism comprising a supporting casing member, a carrier slidable within said casing member, a shaft slidable in said carrier, a toothed element associated with said carrier, a second toothed element associated with said shaft, means for clamping a gear between said toothed elements", and means for moving said carrier and gear into gear lapping position, a lap support, a lap supported thereon, and means for eiiecting relative reciprocation of said supporting casing member and said lap.

10. In a gear lapping machine, the combination with a lap, of gear engaging mechanism, means for relatively reciprocating said mechanism and lap to efiect lapping of a gear, said gear engaging mechanism including a gear support, means for clamping a gear on the support, and a single operating means for first releasing said clamping means and thereafter displacing said gear out of operative relation with said lap, whereby the gear may be removed and replaced or indexed with respect to the lap.

11. In gear lapping apparatus, gear engaging mechanism comprising a reciprocable support, a carrier associated therewith for rotative and linear movement with respect thereto, means for clamping a gear for movement with said carrier, means for efiecting linear movement of said carrier and gear into gear lapping position, and means for clamping said carrier against rotation relative to said reciprocable support when in gear lapping position, a lap support, a lap supported thereon, and means for effecting relative reciprocation of said reciprocable support and carrier and said lap.

12. In gear lapping apparatus, gear engaging mechanism comprising a reciprocable support, a carrier associated therewith for rotative and linear movement with respect thereto, means for clamping a gear for movement with said carrier, means for effecting linear movement of said carrier and gear into gear lapping position, and toothed means for clamping said carrier against rotation relative to said reciprocable support when in gear lapping position, a lap support, a lap supported thereon, and means for effecting relative reciprocation of said reciprocable support and carrier and said lap.

- 13. In gear lapping apparatus, gear engaging mechanism comprising a reciprocable support, a

carrier associated therewith for rotative and linear movement with respect thereto, means for effecting linear movement of said carrier into and out of gear lapping position and means adapted to be actuated by such linear movement of said carrier for clamping a gear against said carrier, said carrier and gear being rotatable together when out of gear lapping position, a lap support, a lap supported thereon, and means for effecting relative reciprocation of said reciprocable support and carrier-and said lap.

14. In gear lapping apparatus having a fixed lap and an axially reciprocable gear support, the combination with a gear carrier mounted on said support for movement with respect to said sup port and said fixed lap, of gear clamping means associated with said carrier, means for moving said carrier relative to said support to withdraw a clamped gear from said fixed lap, and means re sponsive to such movement and effective during the initial part of such movement for automatically releasing saidv clamping means.

15. In gear lapping apparatus having a fixed lap and an axially reciprocable gear support, the combination with a gear carrier mounted on said support for movement with respect to said support and said fixed lap, of gear clamping means associated with said carrier, means for moving said carrier relative to said support to withdraw a clamped gear from said fixed lap, means responsive to such movement for automatically operating said clamping means, and means for reciproeating said support and carrier as a unit to effect lapping of the clamped gear.

JOHN M. CHRISTMAN. 

